Right now, this is just a set of shell scripts to control network conditions between docker containers. In the future, I might make this an actual binary or something.
Requires permissions to write to /usr/bin
$ make install
Note: all commands require root permission. I use this tool in a VM and have
setuid on the tc tool.
$ ctrlnet lat 150ms
$ ctrlnet lat off
$ ctrlnet lat 150ms 10ms # adds a 10ms jitter, normally distributed
$ ctrlnet rate 10mbit # set 5mbit bandwidth cap
Clone the script down, and make sure docker is running, then:
$ docker pull ubuntu
Now, run this twice, in two separate terminals:
$ docker run -ti ubuntu /bin/bash
In one of them, use ip addr to find its ip, and then ping that ip from the
other container. It should be quite low, less than 0.1ms.
Now, on the host, run:
$ ctrlnet lat 40ms
You should see the rtt of the pings spike to 100ms
Then try:
$ ctrlnet lat off
And it will return to normal.
You can also specify your own (as seen above):
$ ctrlnet lat 20ms
This will set a 20ms delay on each link, meaning the total RTT will be 40ms.
Having the same exact latency constantly isnt really how real network work, so if you like, you can throw in some jitter:
$ ctrlnet lat 50ms 5ms
This will add a 5ms jitter to each link, based on a normal distribution, meaning that the total RTT between the nodes should be from 90ms to 110ms